package com.cy.exception.handler;

import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Component;


import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;

/**
 * @author: Luckyh
 * @date : 2021/4/15 19:50
 */

// 限流异常处理类
@Component
public class ServiceBlockExceptionHandler implements BlockExceptionHandler {

    @Override
    public void handle(HttpServletRequest request,
                       HttpServletResponse response,
                       BlockException e) throws Exception {
        // 设置响应数据的编码
        response.setCharacterEncoding("utf-8");
        // 告诉客户端要响应的数据类型以及客户端以什么编码呈现数据
        response.setContentType("text/html;charset=utf-8");

        PrintWriter pw = response.getWriter();
        Map<String,Object> map = new HashMap<>();
        if (e instanceof DegradeException){
            map.put("status", 601);
            map.put("message", "服务器被熔断了");

        }else if (e instanceof FlowException){
            map.put("status", 602);
            map.put("message", "服务器被限流了");
        }else {
            map.put("status", 603);
            map.put("message", "Blocked by Sentinel (flow limiting)");
        }

        // 将map对象转化为jason字符串
        ObjectMapper jasonStr = new ObjectMapper();
        jasonStr.writeValueAsString(map);
        pw.println(map);
        pw.flush();
        pw.close();
    }
}
